There is probably also bias in what crimes are prosecuted (or even reported). Are so-called "white color crimes", like insider trading or tax evasion, reported/prosecuted as frequently as robbing convenience stores? Are all drug crimes handled similarly, or are some drug offenses more socially acceptable than others even if they are both illegal?
All of these prior/historical biases will also be encoded into a predictive system, if that system is trained on the data of the past, which includes such bias...